1. Technical Field
The present invention relates to a liquid ejecting apparatus ejecting liquid such as ink and a control method thereof.
2. Related Art
As a typical liquid ejecting apparatus, there is an ink jet printer of a type in which ink is ejected from a nozzle using a piezoelectric element. In this type of ink jet printer, an ink chamber is provided in each nozzle and the ink is ejected from the nozzle by changing the volume of the ink chamber by driving the piezoelectric element. Hereinafter, the ink jet printer is referred to as “a piezoelectric type ink jet printer”. In the piezoelectric type ink jet printer, it has been known that if the ink is continuously ejected, there is a rise in the temperature of the head drive circuit. Thus, research has been done to prevent the head drive circuit from being overheated. For example, in an ink jet printer of JP-A-2009-056669, the temperature of the head drive circuit is estimated without using a temperature sensor and controlled such that the estimated value does not exceed the limit value, it thereby prevents the head drive circuit from being overheated.
The ink jet printer in JP-A-2009-056669 is a printer in which a head drive circuit is provided in a position (a printer main body) away from the print head. The inventors of the present application have found that there is a case where it is not the increase of the temperature in the head drive circuit, but the increase of the temperature in the print head itself that becomes a problem in this type of printer. That is, the inventors have found that in a case of printing onto a large size print sheet (for example, a sheet of A2 size or higher), the temperature of the print head gradually increases due to heating of the piezoelectric element, so there is a concern that the print head becomes overheated.
Further, in the ink jet printer, it has been desired to stabilize the meniscus of the nozzle or suppress the viscosity of the ink by contriving the waveform of a drive signal (for example, JP-A-2008-044233).
In addition, as shown in FIG. 5 of JP-A-2009-056669, there is a case of using a drive signal including a plurality of drive waveform parts from the related art. If one of a plurality of drive waveform parts is selected and applied to the piezoelectric element, then the residual vibration of the piezoelectric element will be continued to some extent. There is a problem that if the next drive waveform part is applied to the piezoelectric element while the residual vibration exists, a correct amount of ink cannot be ejected.
Further, in the respective ink jet printers, it has been desired to realize a proper ink ejection amount and proper dot formation position according to the characteristics thereof. For example, even in the same type of ink jet printers, research has been desired to realize the proper ink ejection amount and the proper dot formation position for the respective printers according to the manufacture error for the respective printers.
Otherwise, even in the same type of ink jet printer, research has been desired to realize the proper ink ejection amount and the proper dot formation position according to various print modes and print operations (for example, at a time of forward movement and at a time of rearward movement) (for example, JP-A-2003-266700).
In other ink jet printers in the related art, it has been desired to achieve improvement of image quality, longer life spans of components, power saving and stabilization of the circuit operation.
In addition, the aforementioned various problems are not limited to the ink jet printer, but are common to the liquid ejecting apparatus having a head that ejects liquid using the piezoelectric element.